1. Field of the Invention
The present invention relates to a rotary connector for electrically connecting the body and the steering wheel of an automobile, and more particularly to a rotary connector having a rotor housing that can be locked to a stator housing.
2. Description of the Related Art
A conventional rotary connector is disclosed, for example, in Japanese Utility Model Preliminary Publication (KOKAI) No. 1-83287. This conventional rotary connector is provided with a fastening means for fixing a rotor housing, the fastening means engaging a cancel cam sleeve of a turn signal switch such that the fastening means is movable in axial directions of the cancel cam.
When the steering wheel of a vehicle is rotated, the rotary connector mounted on the vehicle is also allowed to rotate through approximately two rotations in each of a clockwise direction and a counterclockwise direction, from a neutral position of the steering wheel at which the vehicle runs straight.
If this rotary connector is assembled to the vehicle at an off-neutral position by mistake, the steering wheel cannot be rotated through two rotations either clockwise or counterclockwise. Forcibly rotating the steering wheel causes the cutting off of the flat cable assembled inside the rotary connector. In order to prevent such an accident, the prior art rotary connectors have a variety of fastening means.
The fastening means disclosed in the aforementioned prior art document is constructed such that when a rotary connector is disposed on the turn signal switch and the steering wheel has not been assembled on the rotary connector, a projection of the rotary connector moves into a cutout formed in a cancel cam of the turn signal switch to prevent rotation of the rotary connector.
When the steering wheel has been assembled on the rotary connector, the cancel cam is pressed against the lower surface of the steering wheel, so that the projection moves out of the cutout to allow the cancel cam to rotate.
The prior art rotary connector and turn signal switch are manufactured at separate plants and delivered separately to a final assembly plant. The rotary connector is assembled on the turn signal switch immediately before the steering wheel is assembled on the rotary connector.
However, the aforementioned prior art rotary connector suffers from the problem that after the turn signal switch has been disengaged from the rotary connector, the projection is out of the cutout and no longer performs a locking function. Thus, the aforementioned prior art rotary connector does not have a locking function if the turn signal switch is not to be assembled to the underside of the rotary connector. Accordingly, the prior art connector cannot be applied to a turn signal switch of a cluster switch type in which the turn signal switch is located beside an instrument panel.
Another type of locking means for a rotary connector is one in which a locking pin is inserted into both the rotor housing and the stator housing to prevent the rotor housing from rotating. With this type of locking means, the locking pin is pulled out of the rotary connector and put aside once the rotary connector has been assembled to the vehicle. Thus, it is uneconomical.
When the rotary connector is disengaged from the steering wheel for the purposes of checking and repairing the steering wheel, the rotor housing cannot be locked since the locking pin has been thrown away and the rotary connector no longer has the locking pin accordingly. If the rotor housing cannot be locked at a predetermined rotational position, the steering wheel may not be assembled properly.
As mentioned above, the rotary connector assembled in the wrong way is unable to rotate through two complete rotations either clockwise or counterclockwise. Attempting to forcibly rotate the steering wheel will cause the cutting off of the flat cable. The cutting of the flat cable leads to a drawback that an air bag, a horn, and the like provided on the steering wheel cannot operate properly.